title: Effect of different membranes on amino-acid losses during haemodialysis.
abstract: BACKGROUND
  We analysed amino-acid losses during haemodialysis, their influence on plasma amino-acid concentration, and their possible effects on nutritional state.
  
  
  METHODS
  Five patients were dialysed with three membranes: cuprophan (CUP), polysulphone (PS), and polyacrylonitrile AN69 (PAN). We compared anthropometric and biochemical parameters after 6 months in patients dialysed with CUP respect to patients with PAN.
  
  
  RESULTS
  Total losses of amino acids were higher with PAN than with PS and CUP (6.1 +/- 2.3 vs 3.8 +/- 1.3, P < 0.05, and 3.7 +/- 1.3 g/session, P < 0.01 respectively). Losses of essential amino acids (EAA) and nonessential amino acids (NEAA) were also higher with PAN respect to PS and CUP (1.8 +/- 0.8 vs 1 +/- 0.3 and 0.8 +/- 0.3, and 4.3 +/- 1.6 vs 2.8 +/- 1 and 2.9 +/- 1.1 g/session, P < 0.05). The percentage reduction for plasma EAA and NEAA were lower with CUP respect to PS and PAN (11 +/- 5% and 20 +/- 14% vs 25 +/- 10% and 33 +/- 11%, and 30 +/- 11% and 25 +/- 17% respectively, P < 0.05). There was no difference in the nutritional state between patients with CUP and PAN. However, plasma valine in patients with PAN was lower than in those with CUP (1.88 +/- 0.12 vs 2.13 +/- 0.32 mg/dl) and almost reached statistical significance.
  
  
  CONCLUSIONS
  New synthetic membranes are advantageous with respect to conventional ones, but a disadvantage is the higher amino-acid losses, especially with polyacrylonitrile. Long-term studies are necessary to evaluate the impact of amino-acid losses on nutritional state in patients dialysed with these membranes.
authors.affiliation: Department of Nephrology, Hospital Ntra. Sra. de Candelaria, S/C de Tenerife, Spain.
authors.forename: J F
authors.initials: JF
authors.lastname: Navarro
authors.forename: R
authors.initials: R
authors.lastname: Marcén
authors.forename: J L
authors.initials: JL
authors.lastname: Teruel
authors.forename: R
authors.initials: R
authors.lastname: Martin del Río
authors.forename: C
authors.initials: C
authors.lastname: Gámez
authors.forename: C
authors.initials: C
authors.lastname: Mora
authors.forename: J
authors.initials: J
authors.lastname: Ortuño
mesh_terms: D000328:Adult; D000368:Aged; D000596:Amino Acids / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D009752:Nutritional Status; D006435:Renal Dialysis
chemical_list: D000596:Amino Acids; D008567:Membranes, Artificial